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211.
The phase diagram of the coupled sine circle map system exhibits a variety of interesting phenomena including spreading regions
with spatiotemporal intermittency, non-spreading regions with spatial intermittency, and coherent structures termed solitons.
A spreading to non-spreading transition is seen in the system. A cellular automaton version of the coupled system maps the
spreading to non-spreading transition to a transition from a probabilistic to a deterministic cellular automaton. The solitonic
sector of the system shows spatiotemporal intermittency with soliton creation, propagation and absorption. A probabilistic
cellular automaton mapping is set up for this sector which can identify each one of these phenomena.
相似文献
212.
G. A. Martínez-Castañón N. Niño-Martínez F. Martínez-Gutierrez J. R. Martínez-Mendoza Facundo Ruiz 《Journal of nanoparticle research》2008,10(8):1343-1348
Silver nanoparticles with different sizes (7, 29, and 89 nm mean values) were synthesized using gallic acid in an aqueous
chemical reduction method. The nanoparticles were characterized using transmission electron microscopy (TEM), dynamic light
scattering (DLS), X-ray diffraction (XRD), and ultraviolet–visible (UV–Vis) absorption spectroscopy; the antibacterial activity
was assessed using the standard microdilution method, determining the minimum inhibitory concentration (MIC) according to
the National Committee for Clinical Laboratory Standards. From the microscopies studies (TEM) we observed that silver nanoparticles
have spherical (7 and 29 nm) and pseudospherical shape (89 nm) with a narrow size distribution. The sizes of the silver nanoparticles
were controlled by varying some experimental conditions. It was found that the antibacterial activity of the nanoparticles
varies when their size diminishes. 相似文献
213.
Wen-Yang Chang Te-Hua Fang Yu-Cheng Lin 《Applied Physics A: Materials Science & Processing》2008,92(3):693-701
Physical characteristics of polyimide films, including optical, micro/nano mechanical, and thermophysical characteristics
were investigated using a photometric, a nanoindentation, and a thermomechanical analyzer for applications in flexible sensors.
Experimental results show that UV light cannot transmit into the polyimide films. The transmittances, with a maximum of about
86%, at VIS and near IR lights decrease with increasing PI film thicknesses. The mechanical characteristics were determined
using tensile, bending moment, and nanoindentation testing. The stress–strain curve approximated bilinear characteristics,
the load–unload bending moment exhibited hysteresis, and nanoindentation generated elastic energy dissipation in the loading–unloading
region. Nanoindentation showed an almost uniform hardness and a reduced Young’s modulus of about 0.181±0.03 and 3.21±0.06 GPa,
respectively, when the penetrating depth was more than about 2 μm. Thermophysical characteristics were greatly influenced
on 8.3 and 25 μm specimens due to the higher relaxation of thin PI films. The thermal expansion remained steady when the thickness
was over 50 μm. The results show that PI films have potential in flexible sensing and higher temperature fabrication. 相似文献
214.
The inflow conditions for spatial direct numerical simulation (SDNS) of turbulent boundary layers should reflect the characteristics
of upstream turbulence, which is a puzzle. In this paper a new method is suggested, in which the flow field obtained by using
temporal direct numerical simulation (TDNS) for fully developed turbulent flow (only flow field for a single moment is sufficient)
can be used as the inflow of SDNS with a proper transformation. The calculation results confirm that this method is feasible
and effective. It is also found that, under a proper time-space transformation, all statistics of the fully developed turbulence
obtained by both temporal mode and spatial mode DNS are in excellent agreement with each other, not only qualitatively, but
also quantitatively. The normal-wise distributions of mean flow profile, turbulent Mach number and the root mean square (RMS)
of the fluctuations of various variables, as well as the Reynolds stresses of the fully developed turbulence obtained by using
SDNS, bear similarity in nature.
Supported by the National Natural Science Foundation of China (Grant No. 90205021), the China Postdoctoral Science Foundation
(Grant No. 20060400707), and the Foundation for the Author of National Excellent Doctoral Dissertation of China (Grant No.
200328), and partially supported by Liu-Hui Center of Applied Mathematics, Nankai University and Tianjin University 相似文献
215.
216.
Background
Lesion studies in human and non-human primates have linked several different regions of prefrontal cortex (PFC) with the ability to inhibit inappropriate motor responses. However, recent functional neuroimaging studies have specifically implicated right inferior PFC in response inhibition. Right frontal dominance for inhibitory motor control has become a commonly accepted view, although support for this position has not been consistent. Particularly conspicuous is the lack of data on the importance of the homologous region in the left hemisphere. To investigate whether the left inferior frontal gyrus (IFG) is critical for response inhibition, we used neuropsychological methodology with carefully characterized brain lesions in neurological patients. 相似文献217.
218.
Quantized Feedback Adaptive Reliable $$H_{\infty }$$ Control for Linear Time-Varying Delayed Systems
Based on an improved \(H_\infty \) performance index, the method of designing a reliable adaptive \(H_\infty \) controller with quantized state is addressed for the time-varying delayed system in this paper. On the basis of online estimates of actuator faults, the controller parameters are updated automatically to compensate the influence of actuator faults on the system while the desired improved \(H_\infty \) performance is preserved. A Lyapunov function candidate is constructed to prove that the closed-loop system is asymptotically stable. And the existing sufficient conditions of the controller are proved to be less conservative. The gains of the controller and the parameters of the adaptive law are co-designed and obtained in terms of solutions to a set of linear matrix inequalities. Finally, two numerical examples are given to illustrate that the proposed method is more effective than the previous methods for time-varying delayed systems. 相似文献
219.
Leonardo Bruno de Sá Maurício Henrique Costa Dias Antonio Carneiro de Mesquita Filho 《Circuits, Systems, and Signal Processing》2016,35(11):3811-3829
Whereas the present practice of designing matching networks for antennas is limited to conventional topologies, requiring a significant amount of domain knowledge, evolutionary algorithms can be used for automatically identifying unconventional designs that are more effective than would otherwise be developed. In this work, an automatic method to design lossless matching networks driven by an evolutionary algorithm (EA) that considers the sensitivities of the network parameters during the synthesis process is presented. To this end, a closed-form expression for the transducer power gain (TPG) sensitivity with respect to the component values is employed in such a way that the effects of the components tolerance on the matching network performance can easily be quantified. A 3D data structure based on the adjacency matrix is conveniently used to represent any type of network topologies. The proposed EA employs a novel set of topology variation operators, tailored for changing the circuit topology, and an association step, with the aim of reducing the number of nodes of the matching circuit. The efficiency of the proposed EA is tested in the synthesis of an impedance matching network for a VHF monopole whip antenna. This study’s results indicate a matching bandwidth improvement, a more uniformly distributed TPG along the operation frequency band and a more stable TPG regarding the components tolerance compared to the results obtained by previous approaches. 相似文献
220.
Kaifang Yang Shuai Wan Yanchao Gong Hong Ren Wu Yan Feng 《Circuits, Systems, and Signal Processing》2016,35(11):4099-4128
This paper presents a novel filtering technique based on sample adaptive offset (SAO) in H.265/high-efficiency video coding (HEVC) for reduction in the temporal flickering artifacts and improving the coding performance. SAO is a newly introduced technique for in-loop filtering in H.265/HEVC, which derives the offsets independently for each frame in the spatial domain without considering temporal frame correlation. As a result, the temporal distortion artifacts which will have a negative effect on the subjective quality, such as flickering artifacts, cannot be effectively addressed. In this paper, the rate-distortion optimization of the newly developed SAO method, referred to as Inter-SAO, is performed on the residual samples between adjacent frames. Inter-SAO and SAO in the reference software of H.265/HEVC (i.e., the test model HM) are then combined to form the novel in-loop filter-based method, denoted as 3D-SAO filtering method, where both spatial information and temporal information are effectively utilized to reduce the overall distortion in reconstructed videos. Compared with the SAO in HM, 3D-SAO has demonstrated its advanced performance for flickering artifacts suppression. Furthermore, 3D-SAO improves the coding efficiency compared with the SAO in HM with a performance gain of up to 0.91 dB in \(\Delta PSNR\), 1.74 dB in \(\Delta PSPNR\) and 7.33 % in BD-rate reduction. 相似文献